import { router, adminProcedure } from '../trpc'
import { z } from 'zod'
import { TRPCError } from '@trpc/server'
import type { Prisma } from '@prisma/client'
import {
  parseRankingCriteria,
  executeAIRanking,
  quickRank as aiQuickRank,
  fetchAndRankCategory,
  type ParsedRankingRule,
} from '../services/ai-ranking'
import { logAudit } from '../utils/audit'
import type { EvaluationConfig } from '@/types/competition-configs'

// ─── Zod Schemas ──────────────────────────────────────────────────────────────

const ParsedRuleSchema = z.object({
  step: z.number().int(),
  type: z.enum(['filter', 'sort', 'limit']),
  description: z.string(),
  field: z.enum(['pass_rate', 'avg_score', 'evaluator_count']).nullable(),
  operator: z.enum(['gte', 'lte', 'eq', 'top_n']).nullable(),
  value: z.number().nullable(),
  dataAvailable: z.boolean(),
})

// ─── Router ───────────────────────────────────────────────────────────────────

export const rankingRouter = router({
  /**
   * Parse natural-language criteria into structured rules (preview mode).
   * RANK-01, RANK-02, RANK-03 — admin reviews parsed rules before executing.
   */
  parseRankingCriteria: adminProcedure
    .input(
      z.object({
        roundId: z.string(),
        criteriaText: z.string().min(1).max(5000),
      }),
    )
    .mutation(async ({ ctx, input }): Promise<ParsedRankingRule[]> => {
      const rules = await parseRankingCriteria(input.criteriaText, ctx.user.id, input.roundId)

      await logAudit({
        prisma: ctx.prisma,
        userId: ctx.user.id,
        action: 'RANKING_CRITERIA_PARSED',
        entityType: 'Round',
        entityId: input.roundId,
        detailsJson: { ruleCount: rules.length },
      })

      return rules
    }),

  /**
   * Execute ranking using pre-parsed rules (confirmed mode).
   * Fetches both categories in parallel, persists a RankingSnapshot.
   * RANK-05, RANK-06, RANK-08.
   */
  executeRanking: adminProcedure
    .input(
      z.object({
        roundId: z.string(),
        criteriaText: z.string(),
        parsedRules: z.array(ParsedRuleSchema),
      }),
    )
    .mutation(async ({ ctx, input }) => {
      // Cast to service type — validated by Zod above
      const rules = input.parsedRules as ParsedRankingRule[]

      // Fetch and rank both categories in parallel
      const [startup, concept] = await Promise.all([
        fetchAndRankCategory('STARTUP', rules, input.roundId, ctx.prisma, ctx.user.id),
        fetchAndRankCategory('BUSINESS_CONCEPT', rules, input.roundId, ctx.prisma, ctx.user.id),
      ])

      // Persist snapshot
      const snapshot = await ctx.prisma.rankingSnapshot.create({
        data: {
          roundId: input.roundId,
          triggeredById: ctx.user.id,
          triggerType: 'MANUAL',
          mode: 'CONFIRMED',
          status: 'COMPLETED',
          criteriaText: input.criteriaText,
          parsedRulesJson: rules as unknown as Prisma.InputJsonValue,
          startupRankingJson: startup.rankedProjects as unknown as Prisma.InputJsonValue,
          conceptRankingJson: concept.rankedProjects as unknown as Prisma.InputJsonValue,
        },
      })

      await logAudit({
        prisma: ctx.prisma,
        userId: ctx.user.id,
        action: 'RANKING_EXECUTED',
        entityType: 'RankingSnapshot',
        entityId: snapshot.id,
        detailsJson: {
          roundId: input.roundId,
          startupCount: startup.rankedProjects.length,
          conceptCount: concept.rankedProjects.length,
        },
      })

      return { snapshotId: snapshot.id, startup, concept }
    }),

  /**
   * Quick rank: parse criteria and execute in one step (RANK-04).
   * Persists a RankingSnapshot with mode=QUICK.
   */
  quickRank: adminProcedure
    .input(
      z.object({
        roundId: z.string(),
        criteriaText: z.string().min(1).max(5000),
      }),
    )
    .mutation(async ({ ctx, input }) => {
      const { startup, concept, parsedRules } = await aiQuickRank(
        input.criteriaText,
        input.roundId,
        ctx.prisma,
        ctx.user.id,
      )

      // Persist snapshot
      const snapshot = await ctx.prisma.rankingSnapshot.create({
        data: {
          roundId: input.roundId,
          triggeredById: ctx.user.id,
          triggerType: 'QUICK',
          mode: 'QUICK',
          status: 'COMPLETED',
          criteriaText: input.criteriaText,
          parsedRulesJson: parsedRules as unknown as Prisma.InputJsonValue,
          startupRankingJson: startup.rankedProjects as unknown as Prisma.InputJsonValue,
          conceptRankingJson: concept.rankedProjects as unknown as Prisma.InputJsonValue,
        },
      })

      await logAudit({
        prisma: ctx.prisma,
        userId: ctx.user.id,
        action: 'RANKING_QUICK_EXECUTED',
        entityType: 'RankingSnapshot',
        entityId: snapshot.id,
        detailsJson: {
          roundId: input.roundId,
          startupCount: startup.rankedProjects.length,
          conceptCount: concept.rankedProjects.length,
        },
      })

      return { snapshotId: snapshot.id, startup, concept, parsedRules }
    }),

  /**
   * List all ranking snapshots for a round (Phase 2 dashboard prep).
   * Ordered by createdAt desc — newest first.
   */
  listSnapshots: adminProcedure
    .input(z.object({ roundId: z.string() }))
    .query(async ({ ctx, input }) => {
      return ctx.prisma.rankingSnapshot.findMany({
        where: { roundId: input.roundId },
        orderBy: { createdAt: 'desc' },
        select: {
          id: true,
          triggeredById: true,
          triggerType: true,
          mode: true,
          status: true,
          criteriaText: true,
          tokensUsed: true,
          createdAt: true,
          triggeredBy: {
            select: { name: true },
          },
        },
      })
    }),

  /**
   * Get a single ranking snapshot by ID (Phase 2 dashboard prep).
   * Returns full snapshot including ranking results.
   */
  getSnapshot: adminProcedure
    .input(z.object({ snapshotId: z.string() }))
    .query(async ({ ctx, input }) => {
      const snapshot = await ctx.prisma.rankingSnapshot.findUnique({
        where: { id: input.snapshotId },
      })

      if (!snapshot) {
        throw new TRPCError({
          code: 'NOT_FOUND',
          message: `Ranking snapshot ${input.snapshotId} not found`,
        })
      }

      return snapshot
    }),

  /**
   * RANK-09 — Manual trigger for auto-rank (admin button on round detail page).
   * Reads ranking criteria from round configJson and executes quickRank.
   */
  triggerAutoRank: adminProcedure
    .input(z.object({ roundId: z.string() }))
    .mutation(async ({ ctx, input }) => {
      const { roundId } = input

      const round = await ctx.prisma.round.findUniqueOrThrow({
        where: { id: roundId },
        select: { id: true, name: true, configJson: true, competition: { select: { id: true } } },
      })

      const config = (round.configJson as EvaluationConfig | null) ?? ({} as EvaluationConfig)
      const criteriaText = config?.rankingCriteria ?? null

      if (!criteriaText) {
        throw new TRPCError({
          code: 'BAD_REQUEST',
          message: 'No ranking criteria configured for this round. Add criteria in round settings first.',
        })
      }

      const result = await aiQuickRank(criteriaText, roundId, ctx.prisma, ctx.user.id)

      const snapshot = await ctx.prisma.rankingSnapshot.create({
        data: {
          roundId,
          triggeredById: ctx.user.id,
          triggerType: 'MANUAL',
          criteriaText,
          parsedRulesJson: result.parsedRules as unknown as Prisma.InputJsonValue,
          startupRankingJson: result.startup.rankedProjects as unknown as Prisma.InputJsonValue,
          conceptRankingJson: result.concept.rankedProjects as unknown as Prisma.InputJsonValue,
          mode: 'QUICK',
          status: 'COMPLETED',
        },
      })

      await logAudit({
        prisma: ctx.prisma,
        userId: ctx.user.id,
        action: 'RANKING_MANUAL_TRIGGERED',
        entityType: 'RankingSnapshot',
        entityId: snapshot.id,
        detailsJson: { roundId },
        ipAddress: ctx.ip,
        userAgent: ctx.userAgent,
      })

      return { snapshotId: snapshot.id, startup: result.startup, concept: result.concept }
    }),

  /**
   * RANK-10 — Retroactive scan: finds all active/closed rounds with autoRankOnComplete
   * configured but no RETROACTIVE snapshot yet, then executes ranking for each.
   * Runs sequentially to avoid hammering OpenAI.
   */
  retroactiveScan: adminProcedure
    .input(z.object({}))
    .mutation(async ({ ctx }) => {
      const rounds = await ctx.prisma.round.findMany({
        where: { status: { in: ['ROUND_ACTIVE', 'ROUND_CLOSED'] } },
        select: { id: true, name: true, configJson: true },
      })

      const results: Array<{ roundId: string; triggered: boolean; reason?: string }> = []

      for (const round of rounds) {
        const config = (round.configJson as EvaluationConfig | null) ?? ({} as EvaluationConfig)
        const autoRankEnabled = config?.autoRankOnComplete ?? false
        const criteriaText = config?.rankingCriteria ?? null

        if (!autoRankEnabled || !criteriaText) {
          results.push({ roundId: round.id, triggered: false, reason: 'auto-rank not configured' })
          continue
        }

        // Check if fully evaluated
        const [total, completed] = await Promise.all([
          ctx.prisma.assignment.count({ where: { roundId: round.id, isRequired: true } }),
          ctx.prisma.assignment.count({ where: { roundId: round.id, isRequired: true, isCompleted: true } }),
        ])

        if (total === 0 || total !== completed) {
          results.push({
            roundId: round.id,
            triggered: false,
            reason: `${completed}/${total} assignments complete`,
          })
          continue
        }

        // Check if a RETROACTIVE snapshot already exists
        const existing = await ctx.prisma.rankingSnapshot.findFirst({
          where: { roundId: round.id, triggerType: 'RETROACTIVE' },
          select: { id: true },
        })
        if (existing) {
          results.push({ roundId: round.id, triggered: false, reason: 'retroactive snapshot already exists' })
          continue
        }

        // Execute ranking sequentially to avoid rate limits
        try {
          const result = await aiQuickRank(criteriaText, round.id, ctx.prisma, ctx.user.id)
          await ctx.prisma.rankingSnapshot.create({
            data: {
              roundId: round.id,
              triggeredById: ctx.user.id,
              triggerType: 'RETROACTIVE',
              criteriaText,
              parsedRulesJson: result.parsedRules as unknown as Prisma.InputJsonValue,
              startupRankingJson: result.startup.rankedProjects as unknown as Prisma.InputJsonValue,
              conceptRankingJson: result.concept.rankedProjects as unknown as Prisma.InputJsonValue,
              mode: 'QUICK',
              status: 'COMPLETED',
            },
          })
          results.push({ roundId: round.id, triggered: true })
        } catch (err) {
          results.push({ roundId: round.id, triggered: false, reason: String(err) })
        }
      }

      await logAudit({
        prisma: ctx.prisma,
        userId: ctx.user.id,
        action: 'RANKING_RETROACTIVE_SCAN',
        entityType: 'Round',
        detailsJson: { results },
        ipAddress: ctx.ip,
        userAgent: ctx.userAgent,
      })

      return {
        results,
        total: results.length,
        triggered: results.filter((r) => r.triggered).length,
      }
    }),
})